Vehicle electronic key system

• US 20060238296A1
• Filed: 04/24/2006
• Published: 10/26/2006
• Est. Priority Date: 04/26/2005
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Konno, Takeshi
• Granted Patent: US 7,852,194 B2
• Time in Patent Office: Days
• US Class Current: 340/5.610
• CPC Class Codes: B60R 2325/306 Motorcycles
• CPC Class Codes: B60R 25/02 operating on the steering mechanism
• CPC Class Codes: B60R 25/1003 Alarm systems characterised by arm or disarm features
• CPC Class Codes: B60R 25/2072 with means for preventing jamming or interference of a remote switch control signal
• CPC Class Codes: B60R 25/245 where the antenna reception area plays a role
• CPC Class Codes: B62H 5/20 indicating unauthorised use, e.g. acting on signalling devices alarm locks in general E05B45/00, e.g. alarm cable or chain lock E05B45/005
• CPC Class Codes: G07C 2009/00349 and the lock having only one limited data transmission range
• CPC Class Codes: G07C 9/00309 operated with bidirectional data transmission between data carrier and locks

Abstract

To ensure a perform authentication based on a request signal Sr which is the authorized radio signal even under a bad radio environment in which radio noise comes continuously. A portable device receives a request signal Sr transmitted from a vehicle-mounted device and transmits an answer signal including a receiving-sensitivity changing switch for changing a receiving sensitivity of a receiving circuit which receives the request signal Sr. As a result, even if the authentication cannot be carried out with normal receiving sensitivity due to the influence of the continuous radio noise, by changing the receiving sensitivity to low sensitivity, and by bringing the portable device physically close to a transmission source of the request signal which is the authorized radio signal, it is possible to dramatically increase the probability that the authentication based on the authorized radio signal can be carried out.

Claims

1. A vehicle electronic key system having a vehicle-mounted device, and a portable device for receiving a request signal transmitted from the vehicle-mounted device and for transmitting an answer signal, the portable device comprising:

a receiving circuit for receiving the request signal;

a receiving-sensitivity changing switch; and

receiving-sensitivity changing control means for changing receiving sensitivity of the receiving circuit on the basis of operation of the receiving-sensitivity changing switch.

2. The vehicle electronic key system according to claim 1, wherein the receiving-sensitivity changing control means changes the receiving sensitivity of the receiving circuit stepwise.

3. The vehicle electronic key system according to claim 1, wherein the receiving circuit includes a low sensitivity receiving circuit and a high sensitivity receiving circuit, and

the receiving-sensitivity changing control means changes the receiving sensitivity by switching between the low sensitivity receiving circuit and the high sensitivity receiving circuit.

4. The vehicle electronic key system according to claim 2, wherein the portable device further comprises a receiving-sensitivity indicator for indicating the current receiving sensitivity resulting from switching operation of the receiving-sensitivity changing switch.

5. The vehicle electronic key system according to claim 3, wherein the portable device further comprises a receiving-sensitivity indicator for indicating the current receiving sensitivity resulting from switching operation of the receiving-sensitivity changing switch.

6. The vehicle electronic key system according to claim 1, wherein the portable device further comprises:

reception possibility determination means for determining, from an output signal of the receiving circuit, whether the situation is such that it is impossible to receive the request signal; and

a reception impossible state indicator which, when the reception possibility determination means determines that the situation is such that it is impossible to receive the request signal, indicates this situation.

7. The vehicle electronic key system according to claim 2, wherein the portable device further comprises:

reception possibility determination means for determining, from an output signal of the receiving circuit, whether the situation is such that it is impossible to receive the request signal; and

a reception impossible state indicator which, when the reception possibility determination means determines that the situation is such that it is impossible to receive the request signal, indicates this situation.

8. The vehicle electronic key system according to claim 3, wherein the portable device further comprises:

reception possibility determination means for determining, from an output signal of the receiving circuit, whether the situation is such that it is impossible to receive the request signal; and

a reception impossible state indicator which, when the reception possibility determination means determines that the situation is such that it is impossible to receive the request signal, indicates this situation.

9. The vehicle electronic key system according to claim 4, wherein the portable device further comprises:

reception possibility determination means for determining, from an output signal of the receiving circuit, whether the situation is such that it is impossible to receive the request signal; and

a reception impossible state indicator which, when the reception possibility determination means determines that the situation is such that it is impossible to receive the request signal, indicates this situation.

10. The vehicle electronic key system according to claim 1, wherein the receiving circuit includes a low sensitivity receiving circuit and a high sensitivity receiving circuit are connected in parallel, and

the receiving-sensitivity changing control means changes the receiving sensitivity by switching between the low sensitivity receiving circuit and the high sensitivity receiving circuit.

11. A vehicle electronic key system having a vehicle-mounted device, and a portable device for receiving a request signal transmitted from the vehicle-mounted device and for transmitting an answer signal, the portable device comprising:

a receiving circuit for receiving the request signal, said receiving circuit includes an antenna and a signal demodulating and amplifying circuit;

a receiving-sensitivity changing switch; and

receiving-sensitivity changing control means for changing receiving sensitivity of the receiving circuit on the basis of operation of the receiving-sensitivity changing switch being operated for a predetermined period of time.

12. The vehicle electronic key system according to claim 11, wherein the receiving-sensitivity changing control means changes the receiving sensitivity of the receiving circuit stepwise.

13. The vehicle electronic key system according to claim 11, wherein the receiving circuit includes a low sensitivity receiving circuit and a high sensitivity receiving circuit, and

the receiving-sensitivity changing control means changes the receiving sensitivity by switching between the low sensitivity receiving circuit and the high sensitivity receiving circuit.

14. The vehicle electronic key system according to claim 12, wherein the portable device further comprises a receiving-sensitivity indicator for indicating the current receiving sensitivity resulting from switching operation of the receiving-sensitivity changing switch.

15. The vehicle electronic key system according to claim 13, wherein the portable device further comprises a receiving-sensitivity indicator for indicating the current receiving sensitivity resulting from switching operation of the receiving-sensitivity changing switch.

16. The vehicle electronic key system according to claim 11, wherein the portable device further comprises:

reception possibility determination means for determining, from an output signal of the receiving circuit, whether the situation is such that it is impossible to receive the request signal; and

a reception impossible state indicator which, when the reception possibility determination means determines that the situation is such that it is impossible to receive the request signal, indicates this situation.

17. The vehicle electronic key system according to claim 12, wherein the portable device further comprises:

reception possibility determination means for determining, from an output signal of the receiving circuit, whether the situation is such that it is impossible to receive the request signal; and

a reception impossible state indicator which, when the reception possibility determination means determines that the situation is such that it is impossible to receive the request signal, indicates this situation.

18. The vehicle electronic key system according to claim 13, wherein the portable device further comprises:

reception possibility determination means for determining, from an output signal of the receiving circuit, whether the situation is such that it is impossible to receive the request signal; and

a reception impossible state indicator which, when the reception possibility determination means determines that the situation is such that it is impossible to receive the request signal, indicates this situation.

19. The vehicle electronic key system according to claim 14, wherein the portable device further comprises:

reception possibility determination means for determining, from an output signal of the receiving circuit, whether the situation is such that it is impossible to receive the request signal; and

a reception impossible state indicator which, when the reception possibility determination means determines that the situation is such that it is impossible to receive the request signal, indicates this situation.

20. The vehicle electronic key system according to claim 11, wherein the receiving circuit includes a low sensitivity receiving circuit and a high sensitivity receiving circuit are connected in parallel, and

the receiving-sensitivity changing control means changes the receiving sensitivity by switching between the low sensitivity receiving circuit and the high sensitivity receiving circuit.